# ===== 6-11.1 =====
class A:
    def greeting(self):
        return "来自A的问候"


class B(A):
    def greeting(self):
        return "来自B的问候"


class C(A):
    def greeting(self):
        return "来自C的问候"


class D(B, C):
    pass

# ===== 6-11.2 =====
d = D()
print(d.greeting())  # 输出什么？
